Well, looks like Greg confirms this explanation. Of course, nobody's asked him what the effect of two objects being simultaneously acted upon was. It's probably not important enough to clog up the queue
Originally Posted by Zergrinch
Since Starro's leg was moved in the adult dimension but not the kid dimension, yet The Light still had it when the worlds merged back together, then does that mean the adult dimension was the "real" world while the kids were sent to a pocket dimension, rather then things just being split? So the airplane is still uncrashed?
No. It means that whatever was ACTED upon takes precedent over what was not acted upon. So the Helmet of Fate stayed in Roanoke. The piece of the creature stayed with Riddler. And Amber's plane crashed.